Filter plug for cigarettes



Aug. 3, 1954 H. BuNzl.

FILTER PLUG FOR CIGARETTES 2 Sheets-Sheet l Filed June 14, 1950 Aug- 3, 1954 H. BUNzL 2,685,344

FILTER PLUG FOR CIGARETTES Filed June 14, 1950 2 Sheets-Sheet 2 I?? x/e 77 for Hujb BUWZZ Patented Atug. 3, 1954 UNITED STATES PATENT OFFICE FILTER PLUG FOR CIGARETTES Application June 14, 1950, Serial No. 167,977

Claims priority, application Great Britain June 22, 1949 (Cl. 18S-45) 4 Claims. 1

This invention relates to filters and more particularly has reference to a filter plug element for use in filter-tip cigarettes.

Filter-tip cigarettes are commonly made on an assembly machine which is supplied with elements of filter plug and elements of cigarette rod, the lengths of these elements being such (e. g. 22 mm, and 110 mm. respectively) that one plug element and one rod element placed end to end have a combined length of twice that of the finished cigarette. The machine forms a composite rod consisting of plug elements alternating with rod elements, and thereafter severs each plug and rod element at the middle of its length so as to divide the composite rod into separate filter-tip cigarettes.

This known machine operates satisfactorily with plug elements consisting of a tube of cigarette paper containing longitudinally creped paper bunched, folded or rolled into a cylinder. Such plug elements, even when formed from crepe paper interleaved with brous filtering material, effect only partial filtering of the tobacco smoke.

Some smokers prefer a more complete filtering such as is provided by filter plugs filled with cotton wool or like fibrous medium. However, the known assembly machine hereinbefcre referred to does not operate satisfactorily with wool-filled lter plugs which are so soft that they are crushed and torn instead of being cleanly severed in the final operation of dividing the composite rod into individual cigarettes.

The principal object of this invention is to overcome this diiculty.

Another object of this invention is to provide a filter plug element consisting of a core composed of wool surrounded by an inner tube of relatively stout paper, e. g. cartridge or parchment paper, having a longitudinal butt joint and in its turn surrounded by an outer tube of relatively thin paper, e. g. cigarette paper, having a longitudinal lapped and stuck seam.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings wherein:

Figure l is a View partly in section and partly in elevation of a machine for forming iilter plug elements in accordance with the invention.

Figure 2 is a plan view of the machine shown in Figure 1.

Figure 3 is a perspective view of a prefolder.

Figure 4 is a section through a filter plug element in accordance with the invention.

Figure 5 is a view of a portion of the machine shown in Figure l and showing an alternative method of applying adhesive to a parchment strip.

A strip IIJ of parchment paper is passed from a storage roll II, through a prefolder I2 against a gluing wheel 39 and over a roller I3 into a garniture I4 (means to supply adhesive toy the glueing wheel 39 are not shown). Simultane-` ously, a sliver of cotton wool is unreeled from a storage roll I6 and is laid onto the top surface of an endless tape I'I which pulls the sliver under wheels I8, I9 and 20. The tape I'I travels in a slot 2l in the top surface of the machine. The wheels I3 and I9 press the sliver on to the tape and compact it, and the wheel 20 co-operates with the tape Il, which has been bent to a U-section by the walls of the slot 2 I, to shape the sliver into a rod of approximately circular cross section. The shaped sliver is laid onto the parchment strip Il! as the strip enters the garniture I.. Also simultaneously, a strip 22 of cigarette paper is unreeled from a storage roll 23, passed through a prefolder 24 and over a roller 25 and is laid onto the underside of the parchment strip I@ as it enters the garniture I4.

In the garniture the parchment strip is bent around the Wool sliver I5 until its two edges meet and form a butt joint IBA (Figure 4). The cigarette paper strip 22 is wrapped around the parchment layer leaving one border 22A projecting more or less radially upwards, which thereafter has one surface covered with paste in known manner by means of a paste wheel 2E and a (5o-operating press or Wheel 21 (means to supply paste to the paste wheel are not shown). The portion 22A is subsequently pressed down by the garniture onto the other border of the cigarette paper layer to form a longitudinal lapped and stuck seam. The paste is dried by an electrically heated iron 28 under which the resultant continuous filter plug rod 29 passes with the seam uppermost. The plug rod 29 is pulled through the garniture by an endless tape 3d which is laid onto the under surface of the cigarette paper strip 22 and is wrapped part way around the outside of the plug rod 29 as it is formed in the garniture (see Figure 4).

The plug rod 29 is cut into separate lengths 29A in known manner by means of a rotating, vertically-reciprocating knife 3|. The knife is arranged to travel with the plug rod as it cuts the rod. Means to operate the knife are not shown. The cut lengths 2SA are picked up by an endless tape 32, pass under another endlesss tape 33 and are pushed from the tape 32 onto a conveyor band 34 by means of a rotating paddle wheel 35. The conveyor band 34 passes the cut lengths 29A to a packing station or to a cigarette-making machine.

Freely pivoted steel bows 3S rest on the storage reels il and 23, acting as friction brakes and maintaining slight tensions in their respective strips,

The gluing wheel 39 has a plain periphery and covers the surface of the parchment strip which contacts the wool sliver with adhesive. Since the Wool core is attached by adhesive to the parchment tube, any tendency in the finished plug element for the wool core to slip out from the parchment tube is prevented. The periphery oi the gluing wheel 38 may be ribbed instead of plain so that lines of adhesive are laid on the parchment surface instead or" the whole surface being covered. In an alternative arrangement shown in Figure 5, the adhesive is sprayed onto the parchment strip i from a nozzle @.0 which is connected to any suitable source (not shown) of adhesive under pressure,

The parchment and cigarette paper strips must be accurately aligned along one edge to ensure that a suicient overlap (22A) of the cigarette paper strip is left at the other edge for a strong seam to be obtained. It must therefore be possible to align the parchment and cigarette paper strips relatively to each other and transversely to their direction of feed. This alignment is done by means of the two prefolders l2 and 24. Each prefolder is capable of movement transversely to the direction of feed of the strips by means of a threaded rod 3'! iitted with a handwheel 38 and is so shaped that it bends its respective strip to a U-section. It is found that when the strips are bent to some section other than linear they respond more readily and accurately to movements of the preformers than they would if they remained flat.

It is preferred practice to feed the two strips separately so that they meet for the first time at the entrance to the garniture. The roller i3 is so placed that the parchment strip ID is spaced about 11/2 mm. above the cigarette paper strip 22 asthe latter passes over the roller 25. If the strips meet before they enter the garniture they tend to wander relative to each other so that they are not accurately aligned when they enter the garniture.

It has been found that it is not advisable to pass the parchment web l0 along the top surface of the machine between the sliver I5 and the tape H. When this is done the parchment strip is sometimes creased and a plug rod of truly circular cross-section cannot then be obtained.

l. A llter plug element consisting of a core composed of wool surrounded by an inner tube of relatively stout paper, having a longitudinal butt joint and in its turn surrounded by an outer tube of relatively thin paper having a longitudinal lapped and stuck seam, the inner tube and the outer tube being of the same length.

2. A filter plug element as claimed in claim l, wherein the said inner tube is of parchment.

3. A lter plug element as claimed in claim l, wherein the wool core is attached by adhesive to the inner surface of the inner tube.

4. A lter plug element as claimed in claim 3, wherein the said inner tube is of parchment.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 636,088 Voron Oct, 31, 1899 1,841,952 Hughes Jan. 19, 1932 1,995,069 Lim Mar. 19, 1935 2,064,239 Aivaz Dec. 15, 1936 2,202,839 Davidson June 4, 1940 2,221,443 Davidson Nov. 12, 1940 2,342,924 Davidson Feb. 29, 1944 FOREIGN PATENTS Number Country Date 5,775 Great Britain Mar. 14, 1908 18,341 Great Britain Aug. 25, 1903 21,735 Great Britain Oct. 25, 1905 297,550 Great Britain Sept. 27, 1928 437,599 Great Britain Oct. 28, 1935 

